Three-component catalyst for olefin polymerization containing alkali metal-aluminum tetraalkyl, transition metal halide, and organophosphorus compound, and polymerizationprocess therewith



United States i atent O Harry W. Coover, Jr., and Frederick B. Joyner,Kingsport, Tenn., assignors to Eastman Kodak Company,

Rochester, N.Y., a corporation of New Jersey 1 No Drawing. Filed Mar.'31, 1958, Ser. No. 724,921

15 Claims. (Cl. 26093.7)

2,973,348 Patented Feb. 28, 1961 of this invention, whereina-monoolefins, either singly or in admixture, are readily polymerizedto-high molec-' This invention relates to a new and improvedpolymerization process and is particularly concerned with the use of anovel catalyst combination for preparing high molecular weight solidpolyolefins, such as poly propylene, of high density and crystallinity.In a. particular aspect the invention is concerned with the preparationof polypropylene and higher po-lyolefins using a particular catalystcombination which has unexpectedly improved catalytic activity and whichgives products characterized by unusually high crystallinity, softeningpoint, thermal stability, stiffness and being substantially free ofnon-crystalline polymers.

Polyethylene has heretofore been prepared by high pressure processes togive' relatively flexible polymers having a rather high degree of chainbranching and a density considerably lower than the theoretical density.Thus, pressures of the order of 500 atmospheres or more and usually ofthe order of 1000-1500 atmospheres are commonly employed. It has beenfound that more dense polyethylenes can be produced by certain catalystcombinations to give polymers which have very little chain branching anda high degree of crystallinity. The exact reason why certain catalystcombinations give these highly dense and highly crystalline polymers isnot readily understood. Furthermore, the activity of the catalystsordinarily depends upon certain specific catalyst combinations, and theresults are ordinarily highly unpredictable, since relatively minorchanges in the catalyst combination often lead to liquid polymers ratherthan the desired solid polymers.

Alkali metal-aluminum tetraalkyls have been suggested for use inconjunction with inorganic halides to produce high molecular weightpolyethylene. Thus, it has been suggested that such tetraalkyls can beused with transition metal halides in the low pressure polymerization ofethylene. When these catalysts are employed to polymerize propylene andhigher a-monoolefins, the resulting polymeric product contains largeamounts of oils, greases and rubbery polymers instead of the desiredhigh molecular weight, crystalline product. Obviously, such results areunsatisfactory when a crystalline polymer is the desired product, and itis one of the purposes of this invention to overcome the undesirableresults obtained when prior art catalysts are used.

This invention is concerned with and has for an object the provision ofimproved processes whereby;- monoolefins and particularly propylene canbe readily polymerized by catalytic means to give high molecular weight,highly crystalline polymers. A particular object of the invention istoprovide an improved catalyst combination which has unexpectedlyimproved catalytic .activity for the polymerization of propylene andhigher a-monoolefins to form crystalline high density polymers. Otherobjects will be apparent from the description and claims which follow.

The above and other objects are attained by means ular weight solidpolymers by effecting the polymeri; zation in the presence of acatalytic mixture containing an alkali metal-aluminum tetraalkyl,wherein each of the alkyl radicals contains from 1 to 12, preferablyl to4, carbon atoms, a halide of a transition metal se lected from the groupconsisting of titanium, vanadium, zirconium, chromium and molybdenum,the halogen at; oms being selected from the group consisting of chlorine, bromine and iodine, and a third component selected from the groupconsisting of esters, amides, and ester.- amides having the formulas:

wherein each Y is an alkylamino (NR or alkoxy OR), said R being analkyl'radical containing 1 to 8, preferably 1 to'4, carbon atoms, andwherein n is an integer of 1 to 4.' The improved catalytic activity ofthis mixture was wholly unexpected, particularly since mixturescontaining only'the tetraalkyls and the metal halides described aboveproduce large amounts of comparatively low molecular weight products inthe polymerization of propylene and higher olefins, and the thirdcomponent of the catalyst is not a known polymerization catalyst. Theinventive process can be carried out in liquid phase in an inert organicliquid and preferably an inert liquid hydrocarbon vehicle, butexcellentre;- sults can be obtained without using a solvent. The process proceedswith excellent results over a tempera:- ture range of from 0 C. to 250C. but temperatures outside this range can be used if desired. Likewise,the reaction pressures may be varied widely from about atmosphericpressure to very high pressures of the order of 20,000 p.s.i. or higher.A particular advantage of the invention is that pressures of the orderof 30-1000 p.s.i. give excellent results, and it is not necessary toemploy the extremely high pressures which were necessary heretofore. Theliquid vehicle employed is desirably one which serves as an inert liquidreaction medium. The invention is of particular importance in thepreparation of highly crystalline polypropylene, the polybutenes andpolystyrene although it can be used for polymerizing mixtures ofethylene and propylene as well as other a-monoolefins containing up to10 carbon atoms. The polypropylene produced in accordance with thisinvention is a highly crystalline polymer that can be used in moldingoperations to form products of excellent clarity. The high molecularweight, high density polymers of this invention are insoluble insolvents at ordinary temperatures but they are soluble in such solventsa's xylene, toluene or tetralin at elevated temperatures. Thesesolubility characteristics make it possible to carry out thepolymerization process under conditions wherein the polymer formed issoluble in the reaction medium during the polymerization and can beprecipitated therefrom by lowering the temperature of the resultingmixture. U I l The novel catalysts described above are particularlyuseful for polymerizing propylene to form a crystalline, high-densitypolymer. The polypropylene produced has a softening point above C. and adensity of0.9l and higher. Usually the density of the polypropylene isofthe order of 0.91 and 0.92.

The polypropylene, polystyrene, polybutenes and other polyolefinsprepared in accordance with-the inver'i'tibn can be molded or extrudedand can be used. toiiorm plates, sheets, films, or. a variety of moldedobjects which exhibit a higher degree of stiffness than do thecorresponding. high pressure polyolefins. The products ,cah be extrudedin the "form of pipe 'or' tubing of excellent rigidity. and can beinjection molded into a great variety of'articl'es. The polymers canalso be cold drawn into ribbons, bands, fibers or filaments of highelasticity and rigidity. Fibers of high strength can be spunfrom themolten polymers obtained according to this. prcess.-

As has'been indicated ahove the improved. results obtained' inaccordance with this invention depend upon the particular catalystcombination, 'Ihus,,one of the components of the catalyst is an alkalimetal-aluminum tetraalkyl; the alkali metal being selected from thegroup consisting of sodium, potassium and lithium, and each of saidalkylradicals containing from 1 to 12fcarbon atoms. Specifically, the alkylradicals can be methyl, ethyl, propyl, butyl, pentyl, hexyl,octyl,,d'odecyl,,and the like, Another component of the catalystcomposition is ahalide of a transition metal selected from the groupconsistingof titanium, vanadium, zirconium, chromium and molybdenum,the-halogen atoms being selected from theigroup consistingof chlorine,bromine and iodine.- The transition metal can be at its maximum valencyor at a reduced valency; Thus, titanium tetrachloride as-wellastit'aniumtrichloride and titanium dichloride can be used" in the catalystcomposition. The 'tliird-componentofthe catalyst composition is anester, an amid Q1- an ester-amide having the formulas:

Each Y represents a lower alkyl'amino or lower alkoxy radical, R is alower alkyl'radical' containing 1"toSi preferably-'1 to 4, carbon atomsand n" integer of"1;to4. Among thespecific compounds that can he usedare tri's- NgN-dimethyl phosphoramide, triethyl phosphate,phosphateester-amides, triethyl'phosphit'e, NgN-dii'nethylacetamide,adipamide and the like.

The limiting factor in the temperature of the'process appears to be thedecompositiontemperature of the-catalyst; Ordinarily temperaturesfrom'50 C." to 150 C. are employed, although temperatures as low-as 0C;canbe employed if desired. Usually,- it not desirable or economical toelfect the polymerization at temperatures below 0 C., and the processcan be readily controlled at room temperature or higher which is' anadvantage from the'standpoint of commercial processing: The pressureemployed is usually only sufficient to-rna'intainreaction mixture inliquid form during thepolymerization, although higher pressures can beused if desired. The pressure is' ordinarily achieved by pressuringthesystem-with the monomer whereby additional monomerdissolves in thereaction vehicle as the polymerization progresses;

The polymerization embodying the. invention can be carried out batchwiseor in a continuous flowingstream process. The continuous processes. arepreferred: for economic reasons, and particularly good results are oh.-taincdusing-continuous processes wherein; a; polymerizationmixture ofconstant compositionaisrcontinuously and progressively introduced intothe polymerizationv zoneand the mixture resulting. from thepolymerization is continuously and progressively withdrawn from thepolymer ization zone at an equivalent rate, whereby the relativeconcentration of the various components in the polymerization zoneremains substantially unchanged during the process. This results information of polymers of extremely uniform molecular weight distributionover a relatively narrow range. Such uniform polymers possess distinctadvantages-since they do not contain any substantial amount of; the lowmolecular weight or high molecular weight formations which areordinarily foundinpolymers prepared by batch reactions- In thecontinuousflowing stream process, the temperatnreis desirably. maintained at asubstantially constant alue t n. he-pr er ed rang n d to c e e s es'desree i ni rmi vi e. ira le 11 P1 5 a o ut on-Qithe mo ome ot e li' hc tia o he. r cs s is des rab effected nd r arra t crimson, 19 0 ps ob nd y P e u ns e y e 4 with the monomer being polymerized. The amount ofvehicle employed can be varied over rather wide limits with relation tothe monomer and catalyst mixture. Best results are obtained using aconcentration of catalyst of from about 0.1% to about.2% by weight basedon the weight of the vehicle. The concentration of the monomer in thevehicl'ewill vary rather widelydependingupon the reaction conditionsand'will usually rangefrom about 2 to 5 0-% by weight. For a-solutionprocess it is preferred to use a concentration from about-2; to about10% by weight based on the weight of the vehicle, and: for a slurry typeof process higher concentrations; for example'up to 40% andhigher'arepreferred'. Higher concentrations-of monomerordinarilyincrease the rate of. polymerization, but concentrations-of5l0% by-weightin a solution process are ordinarily less desirablebecause the polymer dissolved in the reaction medium results in a veryviscous solution.

The molar ratio of tetraalkyl to transition metal halide can bevariedwithin the range of 1:0.5' to 1:2, and the molar ratio of transitionmetalhalide to the thirdcornponent' of the catalytic mixture can bevaried within the range of 1:1 to 1:0.1, but it will be understood'thathigher and lower molar ratios are within the scope of this inven tion. Aparticularly effective catalyst contains one-mole of'transitionmetal'halide and 025 mole'of the third component per mole of tetraalkyl.'Iihe polymerizationtime can be varied as'desired and will usually be ofthe order of from 30 minutes'to several hours in batch processes.Contact times of from 1 m4 hours are commonly employed in autoclave typereactions. When a continuous process'is employed, the contact time inthe polymerization zone can also be regulated asdesired, and in'somecasm itis not necessary to employ reaction or. contact times much beyondonehalf to one hour since a cyclic system can be employed byprecipitation of the polymer and return of the vehicle and unusedcatalyst to the charging zone wherein the catalyst can be replenishedand additional monomer introduced.

The organic vehicle employed can be an aliphatic alkane or cycloalkanesuch as pentane, hexane, heptane or cyclohexane, or a hydrogenatedaromatic compound such as tetrahydronaphthalene or decahydronaphthaleneor a high molecular weight liquid paraffin or mixture of paraffins whichare liquid at the reaction temperature, or an aromatic hydrocarbon suchas benzene, toluene, xylene, or the like, or a halogenated aromaticcompound such as chlorobenzene, chloronaphthalene, ororthodichlorobenzone. The nature of the vehicleis subject toconsiderable variation, although the vehicle employed should be liquidunder the conditions of reaction and relatively inert. The hydrocarbonliquids are desirably employed. Other solvents which can be used includeethyl benzene, isopropyl benzene, ethyl toluene, n-propyl benzene,diethyl benezen's, mono and dialkyl naphthalenes, n-octane,, isooctane,methyl cyclohexane, tetralin, decalin, and any of theother well-knowninert liquid. hydrocarbons.

The polymerization ordinarily is accomplished by merely admixing thecomponents of the polymerization mixture, and no additional heat isnecessary unless it is desired to effect the polymerization at anelevated temperature in order to increase the solubility of polymericproduct in the vehicle. When the highly uniform polymers are desiredemploying the continuous process wherein the relative proportions of thevariouscomponents' are maintained substantially constant, thetemperature is desirably controlled withina relatively narrow range:This is readily accomplished since the solvent vehicle forms a highpercentage of the polymerization-mixture and hence can be heated orcooled'tomaintain the temperature as desired;

The importance ofthe variouscomponents of this reaction mixtureisevident fromthe' factthat" in polymerizing propylene a mixture'of' oneof'the tetraalkyls; and transition metal halide produces large amountsof low molecular weight rubbery polymer. However, when the thirdcomponent Within the scope of this invention is added to the mixture theresulting catalyst composition is highly efiective for polymerizingpropylene to form a highly crystalline high-density polymer.

Thus, by means of this invention polyolefins such as polypropylene arereadily produced using a catalyst com bination that has been found tohave unexpected activity for producing highly crystalline polymer inexcellent yields. The polymers thus obtained can be extruded,mechanically milled, cast or molded as desired. The polymers can be usedas blending agents with the relatively more flexible high pressurepolyethylenes to give any desired combination of properties. Thepolymers can also be blended with antioxidants, stabilizers,plasticizers, fillers, pigments, and the like, or mixed with otherpolymeric materials, waxes and the like. In general, the polymersembodying this invention can be treated in similar manner to thoseobtained by other processes.

From the detailed disclosure of this invention it is quite apparent thatin this polymerization procedure a novel catalyst, not suggested inprior art polymerization procedures, is employed. As a result of the useof this novel catalyst it is possible to produce polymeric hydrocarbons,particularly polypropylene, having properties not heretofore obtainable.For example, polypropylene prepared in the presence of catalystcombinations within the scope of this invention is substantially free ofrubbery and oily polymers and thus it is not necessary to subject suchpolypropylene of this invention to extraction procedures in order toobtain a commercial product. Also polypropylene produced in accordancewith this invention possesses unexpectedly high crystallinity, 'anunusually high softening point and outstanding thermal stability. Suchpolypropylene also has a very high stiffness as a result of theunexpectedly high crystallinity. The properties imparted topolypropylene prepared in accordance with this invention thuscharacterize and distinguish this polypropylene from polymers preparedby prior art polymerization procedures.

The novel catalysts defined above can be used to pro duce high molecularweight crystalline polymeric hydrocarbons. The molecular weight of thepolymers can be varied over a wide range by introducing hydrogen to thepolymerization reaction. Such hydrogen can be introduced separately orin admixture with the olefin monomer. The polymers produced inaccordance with this invention can be separated from polymerizationcatalyst by suitable extraction procedures, for example by washing withwater or lower aliphatic alcohols suchas methanol. 7

The catalyst compositions have been described above as being effectiveprimarily for the polymerization of amonoolefins. These catalystcompositions can, however, be used for polymerizing other a-olefins, andit is not necessary to limit the process of the invention tomonoolefins. Other a-olefins that can be used are. butadiene, isoprene,1,3-pentadiene and the like.

The diluents employed in practicing this invention can be advantageouslypurified prior to use in the polymerization reaction by contacting thediluent, for example in a distillation procedure or otherwise, with thepolymerization catalyst to remove undesirable trace impurities. Also,prior to such purification of the diluent the catalyst can be contactedadvantageously with polymerizable amonoolefin.

The following examples are illustrative of this invention.

Example 1 This example illustrates the relatively large quantity ofrubbery polymer obtained with a catalyst composed of an alkalimetal-aluminum tetraalkyl and a transition metal halide. In anitrogen-filled dry box a l-g. catalyst charge comprising equimolarquantities of sodium aluminum tetraethyl and titanium tetrachloride wasadded to a 500-ml. pressure bottle along with ml. of dry heptane. Thepressure bottle was then capped, removed from the dry box, and attachedto a propylenesource provided by means of a converted Parr hydrogenationapparatus. The mixture was agitated, heated to 55 C. and maintainedunder 30 p.s.i. propylene pressure for six hours. At the end of thisperiod the resulting polymer was washed several times with dry methylalcohol and then with water. The weight of the polypropylene was 18.0 g.having a density of 0.899 and an inherent viscosity of 2.11. Afterextraction of the rubbery polypropylene by the use of butyl ether at 70C., residual highly crystalline polypropylene weighed 7.9 g., had adensity of 0.915 and an inherent viscosity at C. in tetralin of 2.24.

When TiCl replaced TiCL; under the above conditions, a slight increasein crystallinity of the product was noted. The 16.3 g. of polypropylenehad a density of 0.906 and an inherent viscosity of 2.66. Afterextraction with butyl ether, the residual highly crystallinepolypropylene Weighed 9.8 g. and had a 0.9 17 density and an inherentviscosity of 2.87.

Example 2 When the process of Example 1 is repeated using a l-gramcatalyst charge having a 121:0.5 molar ratio of sodium aluminumtetraethyl, titanium tetrachloride, and tris-N,N-dimethyl phosphoramide,the yield of crystalline polypropylene was 18.2 grams with a' density of0.916 andan inherent viscosity of 2.52. Adipamide,N,N-dimethylacetamide, and triethyl phosphite when used in place of thephosphoramide gave similar results.

When TiCl was used in place of TiCl, in the above catalyst system, theyield of crystalline polypropylene was 17.9 grams with a density of0.92, and an inherent viscosity of 3.15. Aryl derivatives such as sodiumaluminum tetraphenyl may be used with equally good results in place ofthe sodium aluminum tetraethyl.

Example 3 This example illustrates the relatively large quantity ofrubbery polymer obtained with a two-component lithium aluminumtetraalkyl catalyst. In a nitrogen-filled dry box a 1-g. catalyst chargecomprising equimolar quantities of lithium aluminum tetrabutyl andtitanium tetrachloride was added to a 500-ml. pressure bottle along with100 ml. of dry'heptane. The pressure bottle was then capped, removedfrom the dry box, and attached to a propylene source provided by meansof a converted Parr hydrogenation apparatus. The mixture was agitated,heated to 70 C., and maintained under 30 p.s.i. propylene pressure forsix hours. At the end of this period, the resulting polymer was washedseveral times with dry methanol and then with water. The weight of thepolypropylene was 18.5 g. having a density of 0.902 and an inherentviscosity of 1.89. After extraction of the rubbery polypropylene by theuse of butyl ether at 70 C., the residual highly crystallinepolypropylene weighed 7.7 g., had a density of 0.915 and an inherentviscosity of 2.02.

When potassium aluminum tetraethyl was used in place of the lithiumaluminum tetrabutyl in the above example, the yield of polypropylene was12.3 g.. having a density of 0.904 and an inherent viscosity of 2.27.After extraction with butyl ether, the residual highly crystallinepolypropylene weighed 5.1 g. and had a 0:917 density and an inherentviscosity of 2.35.

Example 4 When the process of Example 3 was repeated using a l-g.catalyst charge having a 1:1:05 molar ratio-pf lithium aluminumtetrabutyl, titanium tetrachloride-and tris-N,N-dimethyl phosphoramide,the yield of crystalline polypropylene was 14.0 g. with a density of0.918 and an inherent viscosity of 2.59. 1

carbon atoms,

lytic mixture consisting ,essen genteel Example a n aa' rassell si dr aa d Z8Q-t St i less was ea lcd i h 'Z-e set 's 'cha e 'gomprising a23110.1 molar ratio of sodium alumiiin m tetra ethyl, titaniumtrichloride, and tris N,N-dimethyl phosphor-amide. The autoclave wascapped, removed from the dry box, placed in a rocker, and attached to aPro ylene source A 1 1 (5 ain har of propylene was added, the autoclavewas rocked, heated to 85 C, and maintained there for four hours. Theproduct was isola ed by Washing with dry methanol and then with water. A49.3-gram yield of highly crystalline polypropylene was obtained havinga density of 0.92 and anihherent viscosity of 3.75. i i w The above wasrepeated using adipamide, N,N- dimethyl-acetamir le, triet-hylphosphate, and triethyl phosphit e in place of the tris-N,N-dimethylphosphoramide f htheabe a a s Cb arab resu ts w re ta n in en easExample 6 The process of Example. 5 was used with 0.75 grams of acatalyst having a 1 l:().25'molar ratio of lithium aluminumtetradodecyl, titanium trichloride, and tris- N,N-dimethylphosphoramide. A 41.0-gram yield of polypropylene was obtained having adensity of 0.919

and an inherent viscosity of 3.46.

When titanium tric-hloride in the abovecatalyst is replaced by vanadiumtrichloride, zirconium tetrachloride, chromic chloride, or molybdenumpentachloride, improved yields of polypropylene are realized.

Examp e 7 The process of Example 5 was followed using a 0.1- gramcatalyst charge and using 3-rnethyl-1-butene as the monomer at apolymerization temperature of 1 50, C. 'A 9.5-gram yieldof highlycrystallinepolyrlg-methyll butone was obtained. Similarly, highlycrystalline polyolefins were also obtained byusing 4-rnethyl-l-pentene,l-butene, L- entene, styrene, fluoro styrene, and yiny-lcyclohexane asmonomers in place oi 3-methyl-L-butene.

We claim:

1. In the polymerization of .a-rnonooletinic hydrocarbons containingfrom 2 to 10 carbon atomsto i o-rm solid, crystalline polymer, theimprovement :whiqh 0, prises catalyzing the polymerization with acatalytic ture consisting essentially of an alkali metalaluminpmtetraalkyl, the alkali metalbeing 'seleqted from the gronp consisting ofsodium, potassiurn'and lithium and the ialkyl radicals containing fromHo 12 car on atoms, a l lorlide of a metal selected from-the,grQuRGQrisistingof titanium, z r on um v iu mland mo bdenum an anorganophosphorus compound selected from the group mash n re trialk'vl P1$Phiie i k ah h tst a hexaalkyl phosphoric triamides, the alkyl radicalsin said .organophosphorus' compound. Cqutaining from 1 to "4 v the molarratio ,of alkalimetal-aluminum tetraalkyl to metal chloride beingvvithin the range 9f 1:0.5 to IE2 and the molar ratio of metal chlorideto .organophosphorus compound being within the range of ltl to 120.1.

2Q In the -polymerizationv of propyleneto form solid, crystallinepolymer, the improvement which'comprises e fiecting the polymerization'in the presence of a" cata- 11 .iq fan a a nan-- aluminum tetraallryl;tli'e allr'a i i the group consisting of sodium, potassium and lithiumand the alkyl radicals. containing from 1 to 12 carbon atoms, a chlorideof a metal selected from the group consisting of titanium, zirconium,vanadium,,chromiulm and van an. new f molybdenum and an organophosphoruscompoundselected iro-m the group consisting of itrialkyl 'phosphites,ltr ialkyl phosphates and .hexallgyl phosphoric tijan ides, the alkylradicals in said organophosphorus' compound containing from 1 to 4carbon ,atomsgthe molar ratio-of molar ratio '8 alkali metal;a1uminumtetraalkyl to metal chloride being yyithin the range of 110.5 to 1:2 andthe molar ratio of l chloride to org'anophosp'horus compound beingwithinthfll'eng Qf 1:1 to 1:0.1. 7

3. In the polymerization of propylene to form solid, crystallinepolymer, the improvement which comprises eiiecting the polymerization inliquid dispersion in an inert-organic liquid and in the presence of acatalytic mixture consisting essentially of an alkali metahalumiriumtetraalkyl, the alkali metal being selected from thegroup consisting ofsodium, potassium and lithium and the alkyl radicals containing from 1to 12 carbon atoms, a ti ani m h ride and an p asphp p n selected iromthe group consisting of triallryl phosphites, trialkyl phosphates andhexaalkyl phosphoric triamides, the ai yi ad al n s an h sphqms wm i dcontaining from 1 to 4 carbonatoms, the molar ratio of alkalimetahalnminurn tetraalkyl to titanium chloride being within the range ofl ;,0.5 to 1:2, and the molar ratio of titanium chloride toorganophqsphorus compound being within the rangeof 1:1 to 1:01.

4- In the p lymeri on of Pr p le t form s i crystalline po ym the mp een wh were effecting the polymerization in liquid dispersion in an inertorganic liquid and in the presence of a catalytic mixture consistingessentially of sodium-aluminum tetraethyl, titanium tetrachloride andtris-N,N -dimethyl phosphoramide, the molarratio of sodium-aluminumtetra- .ethyl .to titanium tetrachloride being Within the range of 1:0.5to 1:2 and the molar ratio of titanium tetrachloride .totris-N,N-dimethyl phosphoramide being Within the range of 1:1 to 1:0.1.

5. In the polymerization of propylene to form solid, crystallinepolymer, the improvement which comprises effecting the polymerization inliquid dispersion in an inert organic ,liquid and in the presence of acatalytic mixture consisting essentially of sodiumaluminum tetraethyl,titanium trichloride and tris-N,N-d imethyl phosphoramide, the molarratio of sodium-aluminum tetraethyl to titanium trichloride being withinthe range of 110.5 to 1:2.and the molar ratio of titanium trichloride totris-N,N-dimethyl phosphorarnide -b .eing within the rangeof 1:1 to110.1.

,6. :In the polymerization of propylene to form solid, crystallinepolymer, the improvement which comprises e'fiecting the polymerizationin liquid dispersion in an inert organic liquid and .in the presence ofa catalytic mixture consisting essentially of lithium-aluminumtetrabutyl, .titaniumttetrachloride and ztris-N N dim ihy P1 .phoramide,the molar ratio of lithium-aluminum tetrabutyl to titanium tetrachloridebeing within the range of 1:05 .to 1:2 .andsthe molar ratio of (titaniumtetrachlo- :therangeof 1:1 to 120.1.

7. 111 the polymerization of polylene to -;orm solid, crystalline;polymer, the improvementhwhieh comprises effecting the polymerization,in liquid dispersion in an inert organic liquid and in the presence ofa catalytic mixture consisting essentiallyof sodium-aluminum tetraethyl,titanium ltrichloride ,and triethyl phosphate, the molar ratio ofsodium-aluminum tetraethyl' to titanium trichloride beingtwithintherange of l,;(). 5 to 1 :2 andthe the molar ratio of titaniumtrichloride to triethyl phosphate being within therangeof 1:1 to l:0. l.

8. In'thepolymerization of propylen 19 {mm S d, crystalline polymer, theimprovement which comprises effecting the polymerization in liquiddispersion in an inert organic liquid and in the presence of a catalyticmixture consisting essentially of sodium-aluminum tetraethyl, titaniumvtricliloride and triethyl phosphite, the

i of sodium aluminum tetraethyl to titanium trichloride1ingfyvithintlierange of 1:0.5 to 152 and ,the moiar iatio offti'taniumtrichloride to triethyl phosphit being yvithin the rangeof l:l,tol:0,l.

9. Asa composition of matter, a polymerization catalyst consistingessentially of an alkali metal-aluminum tetraalkyl, the alkali metalbeing selected from the group consisting of sodium, potassium andlithium and the alkyl radicals containing from 1 to 12 carbon atoms, achloride of a metal selected from the group consisting of titanium,zirconium, vanadium, chromium and molybdenum and an organophosphoruscompound selected from the group consisting of trialkyl phosphites,trialkyl phosphates and hexaalkyl phosphoric triamides, the alkylradicals in said organophosphorus compound containing from 1 to 4 carbonatoms, the molar ratio of alkali metal-aluminum tetraalkyl to metalchloride being within the range of 1:05 to 1:2 and the molar ratio ofmetal chloride to organophosphorus compound being within the rangeof1:1to1:0.1.

10. As a composition of matter, a polymerization catalyst consistingessentially of an alkali metal-aluminum tetraalkyl, the alkali metalbeing selected from the group consisting of sodium, potassium andlithium and the alkyl radicals containing from 1 to 12 carbon atoms, atitanium chloride and an organophosphorus compound selected from thegroup consisting of trialkyl phosphites, trialkyl phosphates andhexaalkyl phosphoric triamides, the alkyl radicals in saidorganophosphorus compound containing from 1 to 4 carbon atoms, the molarratio of alkali metalaluminum tetraalkyl to titanium chloride beingwithin the range of 1:05 to 1:2 and the molar ratio of titanium chlorideto organophosphorus compound being within the range of 1:1 to 1:0.1.

11. As a composition of matter, a polymerization catalyst consistingessentially of sodium-aluminum tetraethyl, titanium tetrachloride andtris-N,N-dimethyl phosphoramide, the molar ratio of sodium-aluminumtetraethyl to titanium tetrachloride being within the range of 1:05 to1:2 and the molar ratio of titanium tetrachloride to tris- N,N-dimethylphosphoramide being within the range of 1:1 to 1:0.1.

12. As a composition of matter, a polymerization catalyst consistingessentially of sodium-aluminum tetraethyl, titanium trichloride andtris-N,N-dimethyl phosphoramide, the molar ratio of sodium-aluminumtetraethyl to titanium trichloride being within the range of 120.5 to1:2 and the molar ratio of titanium trichloride to tris-N,N-dimethylphosphoramide being within the range of 1:1 to 1:0.1.

13. As a composition of matter, a polymerization catalyst consistingessentially of lithium-aluminum tetrabutyl,

titanium tetrachloride and tris-N,N-dimethyl phosphoramide, the molarratio of lithium-aluminum tetrabutyl to titanium tetrachloride beingwithin the range of 1:05 to 1:2 and the molar ratio of titaniumtetrachloride to tris-N,N-dimethyl phosphoramide being within the rangeof1:1to1:0.1.

14. As a composition of matter, a polymerization catalyst consistingessentially of sodium-aluminum tetraethyl, titanium trichloride andtriethyl phosphate, the molar ratio of sodium-aluminum tetraethyl totitanium trichloride being within the range of 1:05 to 1:2 and the molarratio of titanium trichloride to triethyl phosphate being within therange of 1:1 to 1:0.1.

15. As a composition of matter, a polymerization catalyst consistingessentially of sodium-aluminum tetraethyl, titanium trichloride andtriethyl phosphite, the molar ratio of sodium-aluminum tetraethyl totitanium trichloride being within the range of 1:05 to 1:2 and the molarratio of titanium trichloride to triethyl phosphite being within therange of 1:1 to 1:0.1.

References Cited in the file of this patent UNITED STATES PATENTS2,827,446 Breslow Mar. 18, 1958 FOREIGN PATENTS 534,792 Belgium Ian. 31,1955 526,101 Italy May 14, 1955

1. IN THE POLYMERIZATION OF A-MONOOLEFINIC HYDROCARBONS CONTAINING FROM2 TO 10 CARBON ATOMS TO FORM SOLID, CRYSTALLINE POLYMER, THE IMPROVEMENTWHICH COMPRISES CATALYZING THE POLYMERIZATION WITH A CATALYTIC MIXTURECONSISTING ESSENTIALLY OF AN ALKALI METAL-ALUMINUM TETRAALKYL, THEALKALI METAL BEING SELECTED FROM THE GROUP CONSISTING OF SODIUM,POTASSIUM AND LITHIUM AND THE ALKYL RADICALS CONTAINING FROM 1 TO 12CARBON ATOMS, A CHLORIDE OF A METAL SELECTED FROM THE GROUP CONSISTINGOF TITANIUM, ZIRCONIUM, VANADIUM, CHROMIUM AND MOLYBDENUM AND ANORGANOPHOSPHORUS COMPOUND SELECTED FROM THE GROUP CONSISTING OF TRIALKYLPHOSPHITES, TRIALKYL PHOSPHATES AND HEXAALKYL PHOSPHORIC TRIAMIDES, THEALKYL RADICALS IN SAID ORGANOPHOSPHORUS COMPOUND CONTAINING FROM 1 TO 4CARBON ATOMS, THE MOLAR RATIO OF ALKALI METAL-ALUMINUM TETRAALKYL TOMETAL CHLORIDE BEING WITHIN THE RANGE OF 1:0.5 TO 1:2 AND THE MOLARRATIO OF METAL CHLORIDE TO ORGANOPHOSPHORUS COMPOUND BEING WITHIN THERANGE OF 1:1 TO 1:0.1.